gistfile1.txt

mysql> CREATE TABLE temp (col1 INT, col2 INT, col3 INT);
Query OK, 0 rows affected (0.02 sec)

mysql> 
mysql> INSERT INTO temp (col1, col2, col3) values (1,2,3);
Query OK, 1 row affected (0.01 sec)

mysql> INSERT INTO temp (col1, col2, col3) values (1,3,4);
Query OK, 1 row affected (0.00 sec)

mysql> select * from temp;
+------+------+------+
| col1 | col2 | col3 |
+------+------+------+
|    1 |    2 |    3 |
|    1 |    3 |    4 |
+------+------+------+
2 rows in set (0.00 sec)

mysql> select col1, col2, sum(col3) from temp group by col1;
+------+------+-----------+
| col1 | col2 | sum(col3) |
+------+------+-----------+
|    1 |    2 |         7 |
+------+------+-----------+
1 row in set (0.00 sec)

mysql>